Begell House Inc.Radio Physics and Radio AstronomyRPRA2152-274X332012PECULIARITY OF CONTINUUM EMISSION FROM THE UPPER SOLAR CORONA AT DECAMETER WAVELENGTHS187-196A. I.BrazhenkoPoltava Gravimetric Observatory, Subbotin Institute of Geophysics National Academy of Sciences of Ukraine, 27/29 Myasoedov St., Poltava 36029, UkraineA. A. KovalInstitute of Radio Astronomy, National Academy of Sciences of UkraineAlexandr A.KonovalenkoInstitute of Radio Astronomy of the National Academy of Sciences of UkraineA. A.StanislavskyInstitute of Radio Astronomy, National Academy of Sciences of UkraineE. P.AbraninInstitute of Radio Astronomy, National Academy of Sciences of UkraineV. V.DorovskyInstitute of Radio Astronomy, National Academy of Sciences of UkraineV. N.MelnikInstitute of Radio Astronomy, National Academy of Sciences of UkraineR. V.VashchishinPoltava Gravimetric Observatory of the Institute of Geophysics, National Academy of Sciences of Ukraine, 27/29, Miasoedov St.,Poltava,36029A. V.FrantsuzenkoPoltava Gravimetric Observatory of the Institute of Geophysics, National Academy of Sciences of Ukraine, 27/29, Miasoedov St.,Poltava,36029O. V. BorysyukPoltava Gravimetric Observatory, Subbotin Institute of Geophysics, National Academy of Sciences of Ukraine, 27/29, Myasoedov St., Poltava, 36029, UkraineThe results of the quiet Sun radio emission investigated at decameter wavelengths are presented. The observations have been made with the URAN-2 antenna array in summer seasons of 2008-2009 at 20 and 25 MHz within 250 kHz bandwidth together with the UTR-2 radio telescope in the summer-autumn period of 2010 at 16.5 to 33.0 MHz in the mode of one-dimensional heliograph. The average values of the quiet Sun corona flux density according to URAN-2 measurements are equal to 860 Jy at 25 MHz and 710 Jy at 20 MHz. The values of integral flux density from UTR-2 measurements for these frequencies are 950 and 800 Jy, respectively. The URAN-2 and UTR-2 measured data as respects the spectral index within 16.5−200 MHz have shown it to be the same and equal to −2.1 ± 0.1. The angular sizes of solar corona equatorial diameter have been determined from the UTR-2 observations. The results yielded are in good agreement with the values known for the continuum emission from the solar corona at higher frequencies. Simultaneous application of different geographically spaced radiotelescopes possessing coincident frequency range is shown effective, too.INVERSE COMPTON AND THOMSON SCATTERING OF THE QUASAR 3C 273 EMISSION BY ELECTRONS OF THE NEAREST KNOT OF ITS KILOPARSEC JET197-204M. S. ButuzovaInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Chervonopraporna St., Kharkiv, 61002, UkraineThe X-ray emission of the nearest to the core 3C 273 kiloparsec jet knot A1 is shown to be produced by the inverse Compton scattering of quasar emission rather than by the Thomson scattering. For the last process, a large quantity of thermal plasma is required at the knot, the fact not confirmed by polarization observations. Conclusion is made that the low-energy cut-off occurs at the power-law spectrum of ultrarelativistic electrons in knot A1.PROPAGATION OF TYPE III SOLAR BURSTS RADIO EMISSION THROUGH THE CORONA. 1. TIME PROFILE205-213B. P.RutkevychInstitute of Radio Astronomy, National Academy of Sciences of UkraineV. N.MelnikInstitute of Radio Astronomy, National Academy of Sciences of UkraineThe propagation of electromagnetic waves in the coronal plasma, from the area of generation toward an observer, is considered based on the generally accepted plasma theory of type III burst generation. Special attention is given to the increase in the group velocity of the electromagnetic waves, arising from the variation in the plasma density away from the Sun. An analytic formula for the wave's group velocity as function of the generation area coordinate and of separation from that has been derived. The formula is used to analyze the group delay of the waves within two models of the corona. Taking into account the spatial size of the electron beam, it has become possible to obtain representations for the time profile of the electromagnetic radiation. A fine-structured electron beam has been considered. The radiation profile from such a beam can be shown to resemble closely the observed profile of type III bursts with a fine structure. Also, a spherical beam of a monotonically increasing radius is considered, and the dynamic spectrum of type III bursts is derived. The burst duration has been evaluated over a broad frequency range.PHYSICAL PARAMETERS OF RADIO SOURCES WITH STEEPLY RISING DECAMETER WAVELENGTH SPECTRA215-221A. P.MiroshnichenkoInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Chervonopraporna St., Kharkiv, 61002A sample of extragalactic objects with spectral index magnitudes α ≥ 1, which have been taken from the UTR-2 catalog, is used to analyze the radio sources characterized at decameter wavelengths by a steep rise of their spectra (known as spectral type C+). In the framework of the λCDM model of the Universe, luminosities of the galaxies and quasars belonging to the sample have been estimated for the decameter, centimeter, and optical wave ranges, and estimates obtained for magnetic field strengths, linear sizes and characteristic ages of the objects. Similar to the sources which show steep linear spectra (spectral type S), the galaxies and quasars with type C+ spectra show high values of the radio luminosity and an extended structure at radio frequencies. A relation has been established between linear sizes of the type C+ sources and their low frequency luminosities. A significant cosmological evolution of luminosity has been revealed for the sources considered.MECHANISM OF DEGRADATION OF IMAGES OBSERVED THROUGH A MEDIUM WITH RANDOM INHOMOGENEITIES223-232Y. V.KornienkoO.Ya. Usikov Institute for Radio Physics and Electronics, National Academy of Sciences of Ukraine, 12 Academician Proskura St., Kharkiv 61085, UkraineSergey I.SkuratovskiyO.Ya. Usikov Institute for Radio Physics and Electronics, National Academy of Sciences of Ukraine, 12 Academician Proskura St., Kharkiv 61085, UkraineCauses of degrading object images observed through a medium with random inhomogeneities of the refraction index are analyzed. The mechanism of information degradation due to phase distortions is considered in detail. The existing ways of reaching the diffraction limit of instrument resolution are briefly reviewed and causes of reducing their efficiency in the case of standard deviations of phase distortions equal to 2&#960; or greater are analyzed. A technique is suggested to remove the limit.
BACKGROUND VARIATIONS IN THE TOTAL ELECTRON CONTENT OF THE IONOSPHERE OVER THE ANTARCTIC PENINSULA233-240A. A. SopinInstitute of Radio Astronomy, National Academy of Sciences of UkraineY. M.ZanimonskiyInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Chervonopraporna St., Kharkiv, 61002, UkraineV. N.LisachenkoInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Chervonopraporna St., Kharkiv, 61002, UkraineYu. M.YampolskiInstitute of Radio Astronomy, National Academy of Sciences of UkraineResults are presented of investigated variations in the Total Electron Content (TEC) of the ionosphere over the Antarctic Peninsula using data from a local network of permanent GNSS stations for 450 days in 2009 and 2010. Diurnal dependences of the velocities and motion directions of ionospheric inhomogeneities are analyzed for different seasons. In the daytime, the inhomogeneities move predominantly north-eastward at velocities 300 to 500 m/s for all seasons. During the evening hours in autumn and winter the north-western motion direction is prevailing, while in spring and summer the south-western direction dominates. The nighttime ionospheric inhomogeneities are characterized by wider ranges of motion velocities and directions.
GEOMAGNETIC PULSATIONS ASSOCIATED WITH THE SOLAR TERMINATOR MOTION THROUGH THE MAGNETOCONJUGATE REGION241-250L. F.ChernogorV. Karazin National University of Kharkov, 4, Svoboda Sq., Kharkov, 61077; A. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine, 12, Academician Proskura St., Kharkov 61085, UkraineQuasi-periodic variations in the geomagnetic field within the range of periods 1 to 1000 s as observed near Kharkiv (Ukraine) in 2002 thru 2011 are analyzed with respect to their relation to solar terminator passage through the magnetoconjugate region. The observations have been made for the summer and winter seasons. Quasi-periodic perturbations in the geomagnetic field have been detected which were in advance by 80 to 100 min of the time moment of the solar terminator passage over Kharkiv at the 100 km altitude. The characteristic period of the perturbations was 10 to 12 min, duration 50 to 60 min and amplitude 1 to 2 nT. It is vindicated that the perturbations are transported from the magnetoconjugate region by slow magnetoacoustic waves.
SEARCHING THE "WEEKEND EFFECT" IN INTENSITY VARIATIONS OF THE NATURAL ELF NOISE251-257A. V. PaznukhovInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Chervonopraporna St., Kharkiv, 61002, UkraineYu. M.YampolskiInstitute of Radio Astronomy, National Academy of Sciences of UkraineY. M.ZanimonskiyInstitute of Radio Astronomy, National Academy of Sciences of Ukraine, 4, Chervonopraporna St., Kharkiv, 61002, UkraineA.V.SoinaInstitute of Radio Astronomy, National Academy of Sciences of Ukraine 4, Krasnoznamennaya St., Kharkov 61002, UkraineA review of papers focused on investigating weekly cycles in various environmental parameters is presented. The existing studies are systematized according to the terrain where estimates have been obtained and parameters for which the weekly cycle has been revealed. Weekly variations in air temperature, atmospheric pressure, number of earthquakes, tropospheric ozone concentration, number of forest fires and other parameters are considered. Seven-day variations in the ELF noise intensity are analyzed using data obtained at the Ukrainian Antarctic Station "Akademik Vernadsky" and at the Low Frequency Observatory of the Institute of Radio Astronomy, National Academy of Sciences of Ukraine at Martove village (Kharkiv region, Ukraine). A hypothesis is suggested to explain possible anthropogenic impact on the global thunderstorm activity.OPERATOR METHOD IN THE PROBLEM OF RADIATION FROM AN OPEN END OF A CIRCULAR CORRUGATED WAVEGUIDE259-264M. E. Kaliberda V. Karazin National University of Kharkiv, 4, Svoboda Sq., Kharkov, 61077, UkraineS. A.PogarskyV. Karazin National University of Kharkiv, 4, Svoboda Sq., Kharkov, 61077, UkraineV. A. BelousovV. Karazin National University of Kharkiv, 4, Svoboda Sq., Kharkiv 61022, UkraineThe operator method is applied to the problem of axially asymmetric wave diffraction by an aperiodic system of corrugations in an open-ended circular waveguide. The case is considered when the open end is replaced by a semiinfinite periodic system of corrugations. The frequency dependences of the reflection coefficient and the waveguide radiation field patterns are presented and compared with the results available in the literature.DIFFRACTION EFFECTS IN CYLINDRICAL MONOPOLE AND DIELECTRIC DISK ANTENNAS265-271I. V.IvanchenkoA. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine 12, Academician Proskura St., Kharkov 61085, UkraineN. A.PopenkoA. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine 12, Academician Proskura St., Kharkov 61085M. M.KhruslovA. Usikov Institute of Radio Physics and Electronics, National Academy of Sciences of Ukraine, 12, Academician Proskura Str., Kharkiv 61085, UkraineBased on experimental studies and simulation modelling, the influence of diffraction effects on the radiation characteristics of cylindrical monopole antennas and dielectric disk antennas is determined under conditions when the electrodynamic parameters of antenna components are changed. In particular it is established that the oscillating dependence of the angle of maximum radiation and the resonant frequency of cylindrical monopole antennas with the monopole height dr1 = &#955;/4 as function of the ground plane radius are explained by the different spatial structure of electromagnetic field in the inductive region of the antenna with the ground plane radius multiple of &#955;/2 and of odd number of times &#955;/4 (&#955; is the wavelength in free space). It is shown that the spatial distributions of electromagnetic fields as the "spatial wave grating" are formed in the inductive region of antennas under test.DEALIASING DOPPLER SPECTRA IN METEOROLOGICAL RADARS273-278S. V.SosnytskiyInstitute of Radio Astronomy, National Academy of Sciences of Ukraine A method of dealiasing of Doppler spectra is proposed. The method is based on the fact that overlaid spectral components of the received signals are statistically independent, and that there is no overlay in range. For implementation of the method, the radar is supposed to transmit trains of pulses with two or more pulse repetition frequencies. In contrast to usual dual-PRF techniques, it does not require the Doppler spectrum to be narrow. The method is validated on experimental data from a meteorological radar, the dealiased spectra are compared with those measured directly at higher pulse repetition frequency.